Lens barrel assembly for a camera

ABSTRACT

A lens barrel assembly for a camera is disclosed. The lens barrel assembly comprises a lens barrel, at least one optical element disposed within the lens barrel, and an actuator configured to move the optical element. The actuator can be disposed entirely or partially within the lens barrel. The actuator can be a MEMS actuator, such as a MEMS actuator that is formed at least partially of silicon. The optical element can be a lens.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 12/848,834 filed Aug. 2, 2010 and entitled LENS BARREL ASSEMBLYFOR A CAMERA which is hereby incorporated by reference in its entirety,which is a divisional of and claims the benefit of the priority date ofU.S. patent application Ser. No. 11/565,518 (now U.S. Pat. No. 7,769,284issued Aug. 3, 2010) filed Nov. 30, 2006 and entitled LENS BARRELASSEMBLY FOR A CAMERA which is hereby incorporated by reference in itsentirety, which is a continuation-in-part of and claims the benefit ofthe priority date of U.S. patent application Ser. No. 11/361,608 (nowU.S. Pat. No. 7,813,634 issued Oct. 12, 2010) filed Feb. 24, 2006 andentitled AUTOFOCUS CAMERA which is hereby incorporated by reference inits entirety.

The above-identified U.S. patent application Ser. No. 11/565,518 is alsoa continuation-in-part of and claims the benefit of the priority date ofU.S. patent application Ser. No. 11/078,667 (now U.S. Pat. No. 7,477,842issued Jan. 13, 2009) filed Mar. 11, 2005 and entitled MINIATURE CAMERA.

The above-identified U.S. patent application Ser. No. 11/565,518 is alsoa continuation-in-part of and claims the benefit of the priority date ofU.S. patent application Ser. No. 11/268,849 (now U.S. Pat. No. 7,646,969issued Jan. 12, 2010) filed Nov. 8, 2005 and entitled CAMERA SNUBBERASSEMBLY.

BACKGROUND

1. Field of Invention

This invention generally relates to miniature cameras.

2. Related Art

Miniature cameras are currently available with many electronic devices,such as cellular telephones, laptop computers, personal digitalassistants (PDAs), and the like. Miniature cameras are also available asstand-alone devices for applications such as security and surveillance

The market for miniature cameras is rapidly expanding. For example,camera-equipped cell phones were unheard of just a few years ago; now,they are a significant portion of the cell phone market. However,available miniature cameras may not be optimal for some applications.

For example, available miniature cameras may not be optimal because theyare fixed focus cameras (i.e., the focus of the cameras is pre-set). Byusing a relatively small aperture, the depth of field is sufficient toprovide acceptable focus over a wide range of distances. However, theprovided focus may be unacceptable for some applications. Additionally,the relatively small aperture limits the light used to form the image.This limitation may severely limit the camera's use in low lightconditions.

Some miniature cameras use a flash to enhance camera performance in lowlight conditions. However, the use of a flash consumes more power fromthe batteries, thus requiring more frequent battery charging.

SUMMARY

A lens barrel assembly for a camera is disclosed. The lens barrelassembly can comprise a lens barrel, at least one optical elementdisposed within the lens barrel; and an actuator configured to move theoptical element. The actuator can be disposed either entirely orpartially within the lens barrel and being comprised of silicon.

The optical element can be any desired type of optical element. Forexample, the optical element can be a lens, a shutter, an adjustableaperture, a polarizer, a mirror, a prism, a filter, or a diffractiongrating. The optical element can be any desired combination of elements.For example, the optical element can be a plurality of lenses.

The actuator can comprise a MEMS actuator. The actuator can be comprisedof silicon. For example, the actuator can comprise a comb type siliconMEMS actuator.

The lens barrel can be configured so as to mitigate transmission ofextraneous light to a detector. For example, the lens barrel cancomprise a tubular structure within which the optical element and theactuator are mounted.

More particularly, according to an example of an embodiment of thepresent invention, an optical system can comprise an optical assemblyholder body including a plurality of mounting features sized andpositioned to engage a plurality of optical system elements, theplurality of mounting features including stage mounting features toposition at least a portion of a miniature stage internal to the opticalassembly holder body to selectively position one or more opticalelements in the optical assembly holder body with respect to the opticalassembly holder body.

The plurality of mounting features can comprise a plurality of shuttermounting features configured so as to position at least a portion of ashutter system. The optical system can further include the shuttersystem. The shutter system can include an actuator engaged with theshutter mounting features, and can further include a shutter bladepositioned in a light-receiving portion of the holder body.

A miniature stage can engage with the stage mounting features and bepositioned at least partially in the holder body. A moveable lens can bemounted on the miniature stage and positioned in the holder body.

A controller can be in communication with the miniature stage and can beconfigured to position at least the moveable lens to implement at leastone function from the group consisting of autofocus, zoom, and imagestabilization.

A first lens can be mounted in the holder body and can be positioned ata first end portion of the holder body to receive imaging light. Animager system can be positioned at a second end portion of the holderbody opposite the first end portion. The first lens and the imagersystem can substantially block dust from entering the holder body. Theholder body can have an included volume of about 400 cubic millimetersor less.

According to an example of an embodiment of the present invention, amobile electronic device, such as a miniature camera, can comprise anoptical assembly holder body, a miniature stage engaged with mountingfeatures of the holder body and positioned at least partially in theholder body, and an optical element positioned on the miniature stageand within the optical assembly holder body.

One or more embodiments of the present invention can comprise a mobilesecurity device, a cell phone, a mobile computing device, and a personaldigital assistant.

According to an example of an embodiment of the present invention, amethod of producing a miniature camera, comprises providing a holderbody comprising a plurality of mounting features sized and positioned toengage a plurality of optical system elements. The plurality of mountingfeatures can include a stage mounting features to position at least aportion of a miniature stage having an optical element mounted thereon.The portion of the miniature stage can be engaged with the stagemounting features so that the optical element is positioned in theholder body.

Prior to engaging the portion of the miniature stage with the stagemounting features a first lens can be positioned in the holder body, abaffle can be positioned in the holder body so that a first side of thebaffle is positioned proximate the first lens, and/or a second lens canbe positioned in the holder body so that the second lens is proximate asecond opposite side of the baffle.

At least a portion of a shutter system can be engaged with mountingfeatures of the holder body. At least a portion of an imaging system canbe engaged with mounting features of the holder body.

An example of an embodiment of the present invention can comprise a lensbarrel assembly for a camera, wherein the lens barrel assembly comprisesa lens barrel, at least one optical element disposed within the lensbarrel, and an actuator configured to move the optical element. Theactuator can be disposed at least partially within the lens barrel andcan be comprised of silicon. The actuator can be a MEMS actuator. Theactuator can be a piezo-electric actuator. The actuator can be avoice-coil actuator.

The optical element can be a lens. The actuator can be disposedcompletely within the lens barrel. The lens barrel can be configured soas to mitigate transmission of extraneous light to a detector. Forexample, the lens barrel can comprise a tubular structure.

These and other features and advantages of the present invention will bemore readily apparent from the detailed description of the exemplaryimplementations set forth below taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of an optical system, according tosome embodiments;

FIGS. 2A to 2C illustrates a method of assembling an optical system suchas that shown in FIG. 1, according to some embodiments; and

FIG. 3 is a schematic diagram of an electronic device including anoptical system such as that shown in FIG. 1, according to someembodiments.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

Systems and techniques provided herein may be used for small and highquality miniature cameras. The cameras may provide advancedfunctionality such as auto-focus (AF), zoom, image stability, and thelike. The cameras may be stand-alone devices, or may be included as partof multi-function devices such as cell phones, personal digitalassistants, or other devices.

Some existing camera systems provide auto-focus, shutter capability,and/or optical zoom. However, these functions are implemented using arelatively large lens system. For example, in one example of an existingcamera system, auto-focus functionality is provided by moving the entirelens barrel over a distance of about 300 microns. Moving this relativelylarge mass over a relatively large distance requires sufficiently largestages and actuators.

Further, two windows are generally needed for dust sealing. Sinceoptical performance can be compromised by the presence of dust or otherparticles, sealing the lens systems from the external environment isimportant. However, using two windows increases both the size and thecost of the camera. Currently, the most compact widely available camerawith auto-focus (without shutter or zoom) measures about 10×10×6.7 mm.

By contrast, embodiments described herein allow for a size reduction toabout 8×8×5 mm or less (about half the volume), even when shutter and/orzoom functionality are incorporated.

In commonly assigned U.S. patent application Ser. No. 11/219,410 (nowU.S. Pat. No. 7,729,603 issued Jun. 1, 2010), filed on Sep. 2, 2005,which is hereby incorporated by reference in its entirety, systems andtechniques for moving one or more individual lenses with respect to thelens barrel are described.

The current disclosure allows for movement of one or more opticalelements positioned in the lens barrel with respect to other opticalelements and/or with respect to the lens barrel itself. FIG. 1 shows across-sectional view of a lens system 100, according to someembodiments.

System 100 includes a holder body such as lens barrel body 110, whichmay be a plastic injection molded part. Lens barrel body 110 isconfigured and sized to position and align other components of system100. For example, lens barrel body 110 may include mounting featuressized and configured to engage with and position a plurality of opticalsystem elements such as a miniature stage, one or more fixed lenses,shutter system elements, and the like. Although FIG. 1 illustrates lensbarrel body 110 as a single piece, it need not be.

System 100 further includes a plurality of lenses such as lenses 120A,120B, 120C, and 120D. For a fixed focus miniature camera, each of thelenses may be fixed (directly or indirectly) to lens barrel body 110.For a miniature camera providing enhanced functions, such as auto-focus,zoom, image stabilization, or the like, at least one of the lenses ismoveable. In system 100, lens 120C is positioned on amicro-electromechanical systems (MEMS) stage 140, and may be moved byapplying a force to stage 140 using one or more actuators. A controller190A may provide positioning information to an actuator of stage 140,where the positioning information is indicative of a target position forstage 140 (e.g., a target position corresponding to a desired focuscondition, etc.) The positioning information may comprise positioningdata and/or a signal indicating the desired position of stage 140.

System 100 may further include one or more baffles (not shown). Bafflesmay be provided in lens barrel body 110 between lenses, and positionedto block stray light from an imager 130.

System 100 may further provide physical shuttering capability using ashutter system 150 including a shutter 151 and an actuator 152. Shutter151 may be located behind lens 120A, and may be positioned to blocklight incoming from lens 120A or allow the light to pass. A controller190B (which may be at least partially integrated with controller 190A,or may be separate) is configured to control shuttering.

As noted above, system 100 may implement at least one of auto-focus,image stabilization, shutter, and zoom functions. Auto-focus is animportant feature for miniature cameras. Many available miniaturecameras (such as most cameras found in cell phones) are fixed focuscameras. Although fixed focus is sufficient for some uses, the imagequality is poor for others.

System 100 may implement auto-focus as follows. Lenses 120A, 120B, and120D are fixed to lens barrel body 110. In order to mount the lensesaccurately, lens barrel body 110 is fabricated so that portions of itsinner diameter are precisely matched to the outer diameter of one ormore associated lenses. In the example of FIG. 1, when lenses 120A,120B, and 120D are inserted in lens barrel body 110, they are preciselyaligned by the mounting features of lens barrel body 110. Alignment ofthe lenses is important for obtaining good image quality. For example,lens barrel body 110 may be fabricated within tolerances that allow forlenses 120A, 120B, and 120D to be centered with respect to each otherwith an accuracy of about ±1 micron to about ±20 microns.

Lens 120C is aligned to the other lenses by properly positioning stage140. For example, stage 140 may be abutted to a portion of lens barrelbody 110 in a way that provides intimate contact. Prior to installationof stage 140 and lens 120C in lens barrel body 110, lens 120C is alignedto stage 140 using lens alignment features, such as those described inU.S. patent application Ser. No. 11/364,100 (now U.S. Pat. No. 7,359,130issued Apr. 15, 2008), filed on Feb. 28, 2006, which is herebyincorporated by reference in its entirety.

Many different configurations of stage 140 may be used. For example,stage 140 may be configured to provide translation in one or more of thex, y, and z directions. In some embodiments, the stage may be orienteddifferently than shown; for example, it may be orthogonal to the z-axis,where the motion of the lens is still substantially in the z-axis.Additionally, stage 140 may have multiple parts, so that more than oneoptical element may be positioned in lens barrel body 110.

System 100 may be incorporated in a miniature camera configured toreceive a signal indicating that the miniature camera should obtain animage (e.g., a miniature camera in which a user may press a button toindicate the start of image acquisition). In response to the signal, aposition of lens 120C may be determined that corresponds to a desiredfocus condition, based on objects in the field of view of the camera. Asignal may be generated to drive the actuator of stage 140 so that lens120C is moved to the proper position. One exemplary method forgenerating signals to quickly and accurately move stage 140 to a desiredposition is described in U.S. patent application Ser. No. 11/485,812(now U.S. Pat. No. 7,697,829 issued Apr. 13, 2010), filed on Jul. 12,2006, which is hereby incorporated by reference in its entirety.

Using system 100, stage 140 need only move lens 120C on the order of 40microns to change focus from infinity to 10 cm. This is substantiallyless than the 300 micron movement used in some available systems, wherethe entire lens barrel is moved to focus. The reduced travel is highlydesirable and is a result of moving a lens inside the lens barrel. Thatis, using the systems and techniques herein allows stage 140 to bepositioned substantially (or completely) within the confines of lensbarrel body 110. As a result, substantial size improvements may beobtained with the current systems and techniques.

System 100 may be configured to provide image stabilization, in additionto other features such as auto-focus. In order to implement imagestabilization functionality, stage 140 may be configured to move lens120C in the x- and y-directions (where auto-focus is implemented bymoving lens 120C in the z-direction). By moving lens 120C along thex-axis and/or the y-axis, the position of the image may be shifted withrespect to imager 130 with little affect on focus.

As a result, movement of lens 120C in other degrees of freedom may allowfor optical image stabilization. The motion of the camera may be sensedwith, e.g., inertial rotation sensors. The signal from the sensors maybe processed to determine the motion of lens 120C that will counteractthe motion of the camera to stabilize the image. The processed signalmay then be provided to the actuator(s) of stage 140, which positionslens 120C accordingly.

System 100 may also implement shuttering functionality. As shown in FIG.1, a shutter system 150 includes at least one shutter element 151 and atleast one actuator 152 to apply a force (linear force and/or torque) toa portion of shutter system 150 to position shutter element 151. Shutterelement 151 is positioned between lens 120A and lens 120B tosubstantially block light from entering the other constituents of theoptical system or to allow light to pass.

System 100 may also implement zoom functionality. For example, one ormore additional lenses may be provided that can be positioned in or outof the optical path of system 100. For example, shutter system 150 mayhave an additional lens that can be flipped in and out of the opticalpath. Systems and techniques for implementing zoom are described in U.S.patent application Ser. No. 11/263,152 (now U.S. Pat. No. 7,495,852issued Feb. 24, 2009), filed on Oct. 31, 2005, which is herebyincorporated by reference in its entirety.

FIGS. 2A to 2C illustrate a method that may be used to assemble a lensassembly such as the lens assembly illustrated in FIG. 1.

FIG. 2A illustrates assembly of three of the lenses in the lens holder,which is similar to a process used to assemble state-of-the-art lensbarrel assemblies for cell phone cameras. First, lens barrel body 110 isprovided. Lens 120A is dropped into lens barrel body 110 and pressedinto mounting features 111 formed therein, which are shaped andconfigured to position lens 120A appropriately.

A baffle (not shown) is dropped on top of lens 120A. Lens 120B isdropped on top of the baffle and pressed into mounting features 112formed in lens barrel body 110 configured to position lens 120Bappropriately. A plastic spacer (not shown) is then dropped on top oflens 120B. Lens 120D is dropped on top of the plastic spacer and pressedinto mounting features 113 formed in lens barrel body 110 configured toposition lens 120D appropriately. Glue is then applied to secure lens120D in position, which also secures the other elements as well.

FIG. 2B illustrates the second part of the assembly process. A MEMSshutter blade 151 and actuator 152 are inserted into lens barrel body110 through a slot in its side. The positioning of the shutter isgenerally not critical, so the alignment can be referenced either toshutter blade 151 (for relatively high precision) or actuator body 152(relatively low precision). Shutter blade 151 and actuator 152 may besecured in place using epoxy, or using mounting features with snap-infunctionality.

During this portion of the assembly process, stage 140 and lens 120Cmounted thereon are inserted into lens barrel body 110, engagingmounting features 114. For some applications, the alignment of stage 140and lens 120C are extremely critical. The alignment may be accomplishedin different ways. For example, stage 140 may be referenced to lensbarrel body 110 and secured in place using epoxy, or by implementingmounting features 114 as snap mounting features. In another example,stage 140 can be referenced to the lenses that are already inserted intolens barrel body 110 (e.g., lenses 120B and 120D). In this technique,lens 120C is referenced to stage 140, which in turn is referenceddirectly to lens 120B and 120D. This technique may be more precise thanreferencing stage 140 to lens barrel body 110.

FIG. 2C shows a third portion of the assembly process. Lens barrel body110 includes a skirt portion 116 that protrudes beyond lens 120D. Skirtportion 116 may be generally rectangular in shape and serve as mountingfeatures for imager 130 on PCB 160. Skirt portion 116 provides a sealaround imager 130 when lens barrel body 110 is glued to PCB 160. Thisprovides a very important function, since imager 130 is very sensitiveto dust or other contaminant materials. For example, for animplementation in which imager 130 is configured to provide a threemicron pixel size, a five micron particle that falls on the surface ofimager 130 can make several pixels dark. This may provide anunacceptable image for many applications.

Other embodiments may be used; for example, imager 130 may be a chipscaled package, where the window is mounted directly to the imager chipaccording to chip scale packaging methods for imagers, using knowntechniques. For such an embodiment, the housing rather than the imageris used to align the lenses to imager 130 and to seal the lenses.

A lens barrel body and complete assembly such as the example shown inFIG. 1 may be included in an electronic device such as device 305 ofFIG. 3. Device 305 may comprise a miniature camera, and may providefurther functionality (e.g., it may be a miniature camera included aspart of a device that provides multiple functions).

Miniature camera systems may be used in fixed or mobile devices, whichmay have only camera functionality or may be multi-function devices.

For example, miniature cameras may be provided as part of fixed securitysystems (e.g., mounted to a structure in a fixed position). Alternately,miniature cameras may be integrated with mobile devices, such as mobilesecurity systems (e.g., a camera in a common household item not mountedin a fixed position). Other well-known examples of mobile devicesinclude cell phones, laptop computers, and personal digital assistants(PDAs).

In the implementation of FIG. 3, device 305 includes a miniature cameraconfigured for advanced functionality such as auto-focus, imagestabilization, zoom, shuttering, or the like. As noted above, lensbarrel body 110 includes features for positioning a plurality of lensesin the optical path of imaging light received at a light receiving endof lens barrel body 110.

Although FIG. 3 illustrates a device 305 with a miniature camera havingadvanced functionality, the systems and techniques described herein maybe used with other configurations, such as devices with fixed focusminiature cameras. Additionally, different lens configurations arepossible.

In implementations, the above described techniques and their variationsmay be implemented at least partially as computer software instructions.Such instructions may be stored on one or more machine-readable storagemedia or devices and are executed by, e.g., one or more computerprocessors, or cause the machine, to perform the described functions andoperations.

A number of implementations have been described. Although only a fewimplementations have been disclosed in detail above, other modificationsare possible, and this disclosure is intended to cover all suchmodifications, and most particularly, any modification which might bepredictable to a person having ordinary skill in the art.

Also, only those claims which use the word “means” are intended to beinterpreted under 35 USC 112, sixth paragraph. Moreover, no limitationsfrom the specification are intended to be read into any claims, unlessthose limitations are expressly included in the claims. Accordingly,other embodiments are within the scope of the following claims.

1. A method for manufacturing a device, the method comprising: inserting an optical element within a lens barrel; inserting an actuator at least partially within the lens barrel; wherein the actuator is configured to move the optical element; and wherein the actuator comprises a MEMS actuator and/or a silicon actuator.
 2. The method as recited in claim 1, wherein the optical element comprises a single lens.
 3. The method as recited in claim 1, wherein the optical element comprises a plurality of lenses.
 4. The method as recited in claim 1, wherein the actuator is inserted completely within the lens barrel, and wherein the method comprises inserting the lens barrel with the optical element and the actuator within a multifunction device.
 5. The method as recited in claim 1, further comprising providing an actuator controller configured to control the actuator.
 6. The method as recited in claim 1, wherein the actuator comprises a plurality of actuators configured to translate the optical element in three mutually orthogonal directions.
 7. The method as recited in claim 1, further comprising a shutter at least partially within the lens barrel.
 8. The method as recited in claim 1, wherein the actuator comprises a piezoelectric actuator.
 9. The method as recited in claim 1, wherein the actuator comprises a voice coil actuator.
 10. The method as recited in claim 1, wherein the actuator comprises the MEMS silicon actuator, which is made of silicon.
 11. The method as recited in claim 1, wherein the lens barrel is configured to mitigate transmission of extraneous light to an imager disposed within the lens barrel.
 12. The method as recited in claim 1, wherein the lens barrel comprises a generally tubular structure.
 13. The method as recited in claim 1, wherein the device is a multifunction device comprising a cellular telephone or a personal digital assistant.
 14. A method for operating a device, the method comprising: moving at least one optical element with a MEMS actuator; wherein the at least one optical element is within a lens barrel; and wherein the MEMS actuator is at least partially within the lens barrel.
 15. The method as recited in claim 14, wherein the MEMS actuator is a silicon MEMS actuator.
 16. The method as recited in claim 14, wherein the at least one optical element comprises a single lens.
 17. The method as recited in claim 14, wherein the at least one optical element comprises a plurality of lenses.
 18. The method as recited in claim 14, wherein the MEMS actuator is disposed completely within the lens barrel.
 19. The method as recited in claim 14, further comprising providing an actuator controller configured to control the MEMS actuator.
 20. The method as recited in claim 14, further comprising a shutter at least partially within the lens barrel.
 21. The method as recited in claim 14, wherein the lens barrel is configured to mitigate transmission of extraneous light to an imager disposed within the lens barrel.
 22. The method as recited in claim 14, wherein the lens barrel comprises a tubular structure.
 23. The method as recited in claim 14, wherein the optical element is configured to translate in one direction to facilitate autofocus.
 24. The method as recited in claim 14, wherein the optical element is configured to translate in three mutually orthogonal directions.
 25. The method as recited in claim 14, wherein the optical element is configured to translate in three mutually orthogonal directions to facilitate autofocus and optical image stabilization.
 26. The method as recited in claim 14, wherein moving at least one optical element with a MEMS actuator is controlled by executing instructions with a computer processor and the instructions are stored on machine-readable storage media.
 27. A method comprising: moving a lens in one direction to facilitate focusing of a camera; moving the lens in at least one other direction to facilitate optical image stabilization of the camera; and wherein the lens is moved with a MEMS actuator disposed at least partially within a lens barrel. 